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My Stang is Sick!!! Help needed

  • Thread starter Thread starter IBChillin32182
  • Start date Start date Aug 28, 2005

IBChillin32182

Founding Member
Mar 23, 2000
167
0
16
Shepherdsville, KY
Aug 28, 2005
#1
  • Aug 28, 2005
  • #1
About a week ago I noticed my engine was starting to have a rougher idle than normal. A couple days later on the way home my check engine light started coming on whenever I coasted or hit the brakes with the car in gear between 2000 and 1500 rpm but as soon as i gave it any gas it would go right back off. It doesnt come on every time I decelerate or coast its more like every 3rd or 4th time. The idle has gotten worse over the past few days and now it will surge between 700 and 900 rpm after a cold start and idles really low like around 550 to 600 whenever the a/c is on. The only thing I have done to the car in the past few weeks was clean the k&n filter. I thought some of the oil may have gotten on the mass air sensor but i cleaned it with brake parts cleaner and it didnt help. Any ideas???? Also, will I be able to pull any codes since it is not a constant check engine light?
 

bubba-dough

Active Member
Dec 28, 2004
1,044
2
38
Indiana
Aug 28, 2005
#2
  • Aug 28, 2005
  • #2
As long as the battery hasn't been unhooked the codes should be there.
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
33
129
Aug 29, 2005
#3
  • Aug 29, 2005
  • #3
Agreed with Bubba. The KAM retains the codes.
There might be an EGR code there, but no need to guess - post the codes once you find a paperclip.

Good luck.
 

IBChillin32182

Founding Member
Mar 23, 2000
167
0
16
Shepherdsville, KY
Aug 29, 2005
#4
  • Aug 29, 2005
  • #4
Well the codes that came up didnt give me any answers so I dropped the stang off at the shop today.
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
33
129
Aug 29, 2005
#5
  • Aug 29, 2005
  • #5
And the codes were? Just curious.

Good luck.
 

IBChillin32182

Founding Member
Mar 23, 2000
167
0
16
Shepherdsville, KY
Aug 29, 2005
#6
  • Aug 29, 2005
  • #6
29- No continuity in Vehicle Speed Sensor
44- Air Management System Inoperative
 

jrichker

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Mar 10, 2000
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Dublin GA
Aug 30, 2005
#7
  • Aug 30, 2005
  • #7
Code 29 - Vehicle Speed Sensor (VSS) is an electronic sender mounted on the speedo pickup gear on the trans. It works the cruse control for both 5 speed and auto trans cars. The VSS is used to tell the computer to speed up the idle as you slow to a stop. This helps keep the engine from stalling when you slow down for a stop sign or stop light.
Check to see if the electrical connector is plugged into it. Clean the connector & contacts with non flammable brake parts cleaner prior to replacing the sensor, as that may fix the problem. The sensor cost is under $30 and it is easy to replace.


Codes 94 & 44 - AIR system inoperative - Air Injection. Check vacuum lines for leaks, & cracks. Disconnect the big hose from smog pump: with the engine running you should feel air output. Reconnect the smog pump hose & apply vacuum to the first vacuum controlled valve: Its purpose is to either dump the pump's output to the atmosphere or pass it to the next valve. The next vacuum controlled valve directs the air to either the cylinder heads when the engine is cold or to the catalytic converter when the engine is warm. Disconnect the big hoses from the back side of the vacuum controlled valve and start the engine. Apply vacuum to the valve and see if the airflow changes from one hose to the next.
The two electrical controlled vacuum valves mounted on the rear of the passenger side wheelwell turn the vacuum on & off under computer control. Check to see that both valves have +12 volts on the red wire. Then ground the white/red wire and the first solenoid should open and pass vacuum. Do the same thing to the light green/black wire on the second solenoid and it should open and pass vacuum.

Remember that the computer does not source power for any actuator or relay, but provides the ground necessary to complete the circuit. That means one side of the circuit will always be hot, and the other side will go to ground or below 1 volt as the computer switches on that circuit.

The computer provides the ground to complete the circuit to power the solenoid valve that turns the vacuum on or off. The computer is located under the passenger side kick panel. Remove the kick panel & the cover over the computer wiring connector pins. Check Pin 38 Solenoid valve #1 that provides vacuum to the first Thermactor control valve for a switch from 12-14 volts to 1 volt or less. Do the same with pin 32 solenoid valve #2 that provides vacuum to the second Thermactor control valve. Starting the engine with the computer jumpered to self test mode will cause all the actuators to toggle on and off. If after doing this and you see no switching of the voltage on and off, you can start testing the wiring for shorts to ground and broken wiring. An Ohm check to ground with the computer connector disconnected & the solenoid valves disconnected should show open circuit between the pin 32 and ground and again on pin 38 and ground. In like manner, there should be less than 1 ohm between pin 32 and solenoid valve #2 and pin 38 & Solenoid valve #1.

If after checking the resistance of the wiring & you are sure that there are no wiring faults, start looking at the solenoid valves. If you disconnect them, you can jumper power & ground to them to verify operation. Power & ground supplied should turn on the vacuum flow, remove either one and the vacuum should stop flowing.
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif
 

IBChillin32182

Founding Member
Mar 23, 2000
167
0
16
Shepherdsville, KY
Sep 1, 2005
#8
  • Sep 1, 2005
  • #8
I got my car back from the shop yesterday and they could not find anything wrong besides the code 44 problem. They pin tested some of the other sensors to check to see if they were in spec and they were so they gave me the car back free of charge. Thanks for the reply jrichker, I will try your test tomorrow and see what I find.
 
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